Method of producing printing plates



Dec. 15, 1936. E. CRIST METHOD OF PRODUCING PRINTING PLATES Filed Oct. 11, 1935 3 Sheets-Sheet 1 MM EDGAR I.

Dec. 15, j E LLCRIST I METHOD OF PRODUCING PRINTING PLATES Filed Oct. 11, 1955 a Sheets-Sheet 2' 4 .Jmwm 42 46 43 46 EDGARL-CRIST,

(Sb-M 1 (SM Patented Dec. 15, 1936 UNITED STATES PATENT oFFiCE-g 'METHOD OF rnonucme PRINTING PLATES I Edgar-L. Grist, Dayton, Ohio Application October 11, 1935, Serial No. 44,586

17 Claims. (ci.1o1 4o1.1)

This invention relates to methods of treating printing plates, and in particular, to methods of treating printing plates to produce portions of varying elevations thereon.

One object of this invention is to provide a method of treating a printing plate wherein operations are performed on the printing face of the plate to place diiferent portions of the plate at different elevations or depressions relatively to the remainder of theplate.

Another object is to provide a method of treating printing plates to produce surfaces of different elevations or depressions, including the employment of a matrix having portions thereof raised to diiferent heights, these portions being placed against the corresponding portions of the printing plate and pressure applied to cause the contacting portions of the printing plate to be indented by amounts corresponding to the ele- '0 vations upon the various portions of the matrix.

Another object is to provide a method of treating printing plates wherein curved as well as flat plates may be so treated, and wherein the printing plate may, be given its curvature before it is treated to place its several portions at different elevations or depressions relatively to the remainder of the'plate.

Another object is to provide a method of treating printing plates to difierently elevate or, de-

80 press the different portions of the plate, comprising providing a matrix with raised portions thereon, applying this matrix with the raised portions in contact with the corresponding portions of the plate, and applying pressure to the matrix and the printing plate in such a manner as to cause the'elevations on the matrix to produce corresponding depressions on the printing plate, the metal thus displaced being forced outward to form elevations upon the back of the printing Another object is to provide a method of treating printing plates as described above, wherein the various elevations thus produced on the-back L5 of the printing plate are removed so that an even surface is produced, whereupon the printing plate may be placed in a printing press and operated immediately without any further treatment by matrices, shims or other devices com- 0 'mon in former processes. I

Another object is to provide a method of treating printing plates wherein proofs are taken from the printing plate and portions thereof cut out and secured to the corresponding portions of a. proof secured directly to a support. the requisite number of layers being employed to build up the different parts of the matrix to the necessary height, the matrix thus formed being placed in engagement with the printing plate with the corresponding portions in alignment, and then subjected to pressure at spaced points, this pressure causing the raised portions on the matrix to penetrate the printing surface of the printing plate and force the displaced metal outward from the back surface of the printing plate into the 10 spaces between the points at which such pressure is applied. Another object is-to provide a method of treating a printing plate to produce portions thereon of differing elevations, wherein the differently. 15

elevated portions are produced by direct action upon the printing face of the printing plate rather than by indirect actionuponthe back of. the printing plate. Another object is to tus for applying and matrix.

In the drawings: I Figure 1 is a cross section" prepared fiat matrix employed this invention.

Figure 2 is a cross section along the lineZ-I through a part of Figure 3, showing the'flat matrix of Figure 1 with portions thereof raised above the surrounding portions by securing shin'r-like pieces of material thereto. 1

Figure 3 is a plan view of a matrix with certain areas thereof having raised portions applied thereto, as shown in Figure 2.

Figure 4 is a crosssection through a flat printing plate before its treatment with the matrix of Figures 2 and 3.

Figure 5 is a cross section through the flat printing plate of Figure the matrix of Figures 2 and 3.

Figure, 6 is a longitudinal section through a form of roller used for applying pressure to the back of the printing plate whileit is in engagement with the matrix. I y

Figure 7 is a cross section through a completed flat printing plate, similar to Figure 5 but after the projections-upon the back surface theieof have been removed, as by shaving; I I

Figure 8 is a diagrammaticview, partly 'in' cross section, of a machine for force curved printing plates-into proper engagement with their-matrices.

Figure 9 is a cross section through a partially prepared curved matrix. r

Figure 10 is a cross section through a com- Droyide improved appara- 6 pressure to the printing plate in the method "of 25 4 after treatment with pp ying pressure to pleted curved matrix, with portions of diflerent elevation thereon.

Figure 11 is a cross section through a curved printing plate before its treatment with the curved matrix of Figure 10. 1

Figure 12 is a fragmentary diagrammatic view, partly in section, showing a portion of the machine of Figure 8 during its action in forcing the raised portions of the matrix into the printing plate to form indentations therein and corresponding raised portions on the back thereof.

b Figure 13 is an enlarged layout viewof a portion of the surface of the pressure roller shown in Figures 6 and 12. v

Figure 14 is a cross section through the printing plate after its treatment with the matrix of Figure 10 by means of the rolling machine of Figure 12.

Figure 15 is a diagrammatic view of a form of machine for removing the projecting portions from the back of the printing plate of Figure 14.

Figure 16 is a cross section through the printing plate after the projecting portions on the back have been removed.

In general, the method of treating printing plates of this invention consists in securing a proof from the printing plate to a support to form a matrix. Other proofs are then taken from the plate, which may be either flat or curved, and portions cut from these proofs and secured to' the corresponding portions of theproof on the matrix, using as many layers as are necessary to create the desired indentation of the corresponding portion on the printing plate. The matrix with its portions of different elevation and. the printing plate are then placed in a machine which forces them into engagement with one another, causing the elevated portions of the matrix to indent the corresponding portions of the plate, the metal displaced appearing as projections on the back surface'of the plate.

In the preferred embodiment the machine for applying this pressure includes a roller or pressure plate by which the pressure is applied at spaced points so that the displaced metal may be pushed into the spaces between these points. The printing plate with its projecting portions on the back thereof is then treated to remove these projections and give it an even back surface. The .printing plate is then ready tobe employed directly in a printing press, without the necessity for mounting it over shims or other matrices. If a curved printing plate is to be .treated it may be given its curvature prior to the treatment of this invention, so that no distortion can .result and no change in the elevations or depressions occur.

Hitherto, plates with portions of different height or depth have been produced by applying shims or matrices-to the back of the printing plate, and pressure then applied, using a matrix A with cutaway portions against the front of 'the printing plate. The pressure causes the back portions to become indented where they are in engagement with the raised portions on the matrix, hence, the displaced metal causes the front face of the plate to become raised in varying amounts, according to the thicknesses of. the

portions on the back matrix.

In this method, however, these operations have to be performed when the printing plate is placed in the printing press, hence, result in a tedious set-up and a considerable loss of time. The use of pairs of matrices requires exact matching of these on opposite sides of the printingplate and a considerable deviation causes misalignment and spoilage of the work. The prior art methods also require the handling of the plate several times and are indirect in' their action because they apply the treatment to the rear surface of the printing plate. Any variation in the hardness of the metal would cause a corresponding variation in the curving had taken place. Consequently, the curving of 9. treated printing plate was a very delicate task and resulted in a considerable loss of the elevations or depressions produced in the treatment. This 'slow process or indirect treatment also results in the tying up of machines over considerable periods of time, thus requiring a greater amount of equipment than with the process of the present invention.

Referring to the drawings in detail, Figure 1 shows in its preliminary stages a matrix, generally designated I, having a supporting plate 2,

preferably of thin metal or other similar material. Secured to this supporting plate 2, as by an adhesive, is a proof 3 taken from the printing plate which is to be treated. This proof is taken in the usual way, and results in an exact repro-- duction of the design or printing on the printing plate. A number of additional proofs are now. taken from the printing plate, and portions of these proofs cut out and caused to adhere to the corresponding portions in the proof 3 of the matrix. The number of layers employed depends upon the depth to which that portion of the printing is to be depressed, and this in turn, de-

pends upon the density of printing which it is I desired that theparticular portionof the printing plate shall produce. For heavy shading or tone a shallower depression of the plate is required than for printing in a light shading 'or tone, the latter requiring a deeper depression of the printing plate portion.

In Figure 2 the matrix I is shown as having single layer portions 4 and 5, a double layer portion 6 and a triple layer portion I secured to the corresponding portions of the proof 3.

. tions of different elevation, is then placed in engagement with the printing face of the printing plate I0 (Figure 4), this printing plate being the one from which the proofs were taken for the making of the matrix I.

Thecross sectional view of Figure 4 is taken through the printing plate in a similar position.

to the cross section of the matrix in Figure 2,

which was taken alongthe line 2-2 of Figure 3.. The printing plate I0 before treatment is thus In the portions 8 and 9 of the proof no additional layers seen to be provided with a'plurality of portions.

II, I2, I3, I4, I5 and I6, of substantially equal heights and separated by the grooves I'I com monly employed. in separating the yarlousportions of the printing plate. The printing plate I0 is now placed in engagement with the matrix I, with the corresponding portions in contact with one another. Thus'the single layer matrix portions 4 and 5 are in alignment with the plate portions II and I 6; the matrix portions 8 and 9 are'in alignment with the printing plate portions I2 and I5; the double layer matrix portion 6 is in alignment with the printing plate portion l3; and the triple layer matrix portion 1 is in alignment with the printing plate portion l4.

Pressure is now applied to force the matrix and the printing plate into firm engagement with one another, this pressure being preferably applied by means'of the roller of Figure 6. The roller I8 is mounted upon the shaft 9 and is provided with a surface having a plurality of toothlike projections 26 thereon. When this roller is pressed down upon the printing plate l0, which in turn is in engagement with the matrix I the plate I is forced downward. The triple layer portion I of the matrix I causes the portion M of the printing plate It! to be indented a corresponding amount so that a triple layer project-ion 2| appears on the back of the printing plate. Similarly, a double layer projection 22 appears on the back of the printing plate I0 opposite the front face portion l3, the latter having been indented by an amount equal to the double layer portion 6 of the matrix. Single layer projections 23 and 24 appear opposite the printing plate portions II and I6, these having a thickness of a single layer.- No projections appear on the back of. the printing plate opposite the portions l2 and I because no shims or raised portions were employed at 8 and 9 on the matrix. Accordingly, the portions l2 and I5 retain their original heights on the printing plate.

. It will be understood, however, that the teeth 20 of the roller l8 may produce slight indentations 25 on the back surface, behind the portions l2 and I5; slightly deeper indentations 26 on the single layer projections 23; double layer indentations 21 upon the double layer projection 22; and triple layer indentations 28 upon the triple layer projection 2|. These indentations occur when the displaced metal is forced outward from the rear surface of the printing plate and is caused to enter the spaces between the teeth 20. The printing plate at this stage of the process has the cross sectional appearance of Figure 5.

At this stage the portions 2 and I5 are at their original levels, the portions II and I6 are depressed approximately one layer, the portion I3 is depressed approximately two layers and the portion I4 is depressed approximately three layers, with approximately corresponding projections on the rear surface 29 of the printing plate. The printing plate of Figure 5 is then placed in any suitable machine or treated by hand to remove the projecting portions 2l, 22, 23 and 24. A shaving machine which shaves off these portions and produces an even surface on the back of the plate has been found suitable for this purpose. This machine is well known to those skilled in the art, is of a conventional pattern and forms no part of the present invention. After the rear surface 29 has been cleared of the various projections 2| to 24, the appearance of the printing plate in cross section resembles that of Fig ure 7 This printing plate is now ready to be placed in the printing press, and may be mounted therein without any further operations other than the usual operations upon ordinary printing plates.

For treating curved printing plates the process follows a similar procedure as in the process of treating flat printing plates, previously described. In the process of this invention, however, the curved printing plate is fully produced in its curved form, and the operations performed upon the curved plate. To this end a matrix, generally designated 30, is prepared, with a proof 3| secured to a curved supporting plate. 32. The proof 3| is taken from the curved printing plate 33 shown in Figure 11, hence, an exact correspondence occurs therebetween. In a manner similar to that previously described for flat plates, other proofs are now taken from the curvedprinting plate 33, and the proper portions thereof cut out and applied in layers to the proof 3| upon the supporting plate 32. For example, the matrix 30 may be provided with single layer portions 34 and 35, a double layer portion 36 and a triple layer portion 31. The portions 38 and 39 are shown as left untreated. The matrix now has the appearance in cross section of Figure 10, and the cross section is taken along a similar line as the alignment, respectively, with the printing plate portions 48, 4|, 42, 43, 44 and 45. The assembly is then placed in any suitable machine, such as the machine shown in Figures 8 and 12, and the printing plate 33 and matrix 30 forced into firm engagement with one another. To this end the machine consists of a base 41 having a suitably curved surface 48 to receive the back surface of the matrix 30. The retaining members 49 clamped to the base 4I-serve to retain the printing plate 33 and matrix 30 in engagement with one another, without slippage therebetween.

The machine is provided with a roller 50, similar in form to the roller l8 used in connection with the production of fiat plates, and mounted upon the shaft 5| supported in the bearing hangers 52. The roller 50 is provided with teeth 53, for the same purpose as the teeth 20 in the roller l8 (Figures 8 and 12). The bearing hangers 52 are secured to an oscillating member 54, as by the bolts 55. The oscillating member 54 is mounted upon the shaft 56, and this in turn, is provided with a gear 51 meshing with a gear 58 upon a countershaft 59. The countershaft 59 also carries a pulley 60, having a belt 6| for driving it.

When power is applied to the belt 6| the oscilq lating member 5.4 is caused to move in an arcuate path around the shaft 56. The roller 58 is then moved firmly into engagement with the rear surface of the printing plate 33, and travels in an arcuate path over this rear surface (Figures 8 and 12). By reason of this pressure the raised portions 34, 35, 36, 31, 38 and 39 are caused to firmly engage the corresponding portions 40, 4|, 42, 43, 44 and 45, and the latter are pushed up ward or are caused to remain stationary, according to the presence or absence of layers on the matrix30.- As these are pushed upward, indenting the printing plate 33, the metal displaced is forced outward beyond the back surface 62. Thus, the single portions 40 and 45 when pressed inward by the single layers 34 and 35 of the matrix 30, produce approximately single layer projections 63 and 64 upon the rear surface 62. The

layerless portions 38 and 39 leave the rear sur-v face 62'substantia1ly level. The double layer matrix portion 36 causes a projecting portion 65 on the back surface 62, immediately opposite the front surface portion 42, which has been indented approximately two layers. The triple layer matrix portion 31 produces approximately a 4- triple layer projection 66 on the back surface 62, immediately, opposite the printing plate portion 43, which is indented or depressed approximately three layers.

The action of the teeth 53 upon the roller 50 causes the unraised portions of the plate to be very slightly indented, as at 61 (Figure 14) The single layer projecting portions 63 and 64 are formed with single layer indentations 68, the

double layer projecting portion 65 is formed with double layer indentations 69 and the triple layer projection 66 is formed with triple layer indentations Ill, the depth of these indentations depending upon the distance the projecting portion is;

forced into the space between the teeth 53 upon the roller 50. The printing plate at this stage of the process is shown in Figure 14.

The projecting portions on the back of the printing plate are now removed in any suitable manner, such as by the shaving machine shown in Figure 15. In this shaving machine the base H is provided with'a curved surface 12, of suitable curvature to receive the printing plate 33. Also provided is a cutter 13 having knives l4 thereon, and mounted for rotation upon the shaft 15. The latter is supported in the bearing hangers 16, secured to the oscillating member 'I'! by the bolts 18. The oscillating member 11 is caused to oscillate around a fixed center (not shown) in a pendulum-like manner.

A bevel gear 19 on the cutter shaft 15 meshes with a bevel gear upon the drive shaft 8|, the latter serving to communicate power by which the cutter 13 is rotated. As the cutter 13 rotates and is simultaneously swung in an arcuate path (Figure 15), it moves across the rear surface 62 of the printing plate, cutting off the projecting portions and producing an even back surface. The printing plate 33 now has the cross sectional appearance shown in Figure 16, and may be placed immediately in a printing press and employed for printing purposes.

In the figures of the drawings illustrating the matrix and printing plate the thicknesses of the various layers have been exaggerated so as to show the various changes more clearly. It will be understood, however, that in the ordinary printing plate and matrix the thicknesses of these layers are very much less than the thicknesses illustrated in the figures.

Thus it will be seen that I have produced a process of treating a printing plate, wherein the operations are performed directly upon the front face or printing face of the printing plate, in-

stead of by the indirect operations upon the back surface, as in the prior art. My process, moreover, is applicable equally to flat or curved printing plates, and is carried out on curved printing plates after these have been curved, in contrast to the prior art wherein the operations are carried out before this curving takes place. The subsequent curving of the printing plate in the prior art caused the heights of the elevations or depressions to be greatly altered, and the accuracy of the work correspondingly impaired. In my process, moreover, the various steps are carried out in auxiliary machines, hence, none of the printing presses is tied up, as in the prior art, where the process must be carried out upon the printing press itself by placing a matrix behind the printing plate.

By my process, moreover, I obtain substantially exact correspondence between the matrix and the printing plate because the portion on the print- 1 ing plate which it is desired to depress is directly and matrix to pressure at a multiplicity of locaengaged by the built-up portion on the matrix, and the process does not depend upon the pushing through of material by a matrix placed against against the back of the plate. As a result of my process I am able to treat a vastly 5 greater number of plates, in a given time, than is possible by the prior art methods, using the same number of men. Furthermore, the process of my invention requires but two handlings of the plate, whereas the prior art processes require at least three or more such handlings. It will be understood that in subjecting the fiat plate to pressure, the pressure roller is caused to travel in a straight line instead of a curve, as in thecase with the curved plate.

I desire to comprehend within my invention such modifications as may be embraced within my claims and the scope of my invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A process of treating a printing plate comprising applying a matrix having elevated portions to the printing plate, subjecting the plate tions with indentations therebetween to produce depressions upon the printing face of the printing plate, and to force the protrusions caused by the printing plate material displaced by the depressing operation upon the back of the printing plate toenter said indentations.

2. A process of treating a printing plate comprising applying a matrix having elevated portions to the printing plate, subjecting the plate and matrix to pressure at a multiplicity of locations with indentations'therebetween to produce depressions upon the printing face of the printing plate, to force the protrusions caused by the printing plate material displaced by the depressing operation 'upon the back of the printing plate to enter said indentations, and removing the displaced plate material from the projections upon the back of the printing plate.

3. A process of treating a printing plate comprising preparing a substantially non-resilient 45 printing plate, applying a matrix having elevated portions to the printing plate, subjecting the plate and matrix to pressure at a multiplicity of spaced locations to produce depressions upon the printing face of the printing plate, and causing the 5f displaced plate material to enter the spaces between said pressure-applying locations.

4. A process of treating a printing plate comprising preparing a substantially non-resilient printing plate, applying a matrix having elevated 64 portions to the printing plate, subjecting the plate and matrix to pressure at a multiplicity of spaced locations to produce depressions upon the printing face of the printing plate, causing the displaced plate material to enter the spaces be- 6 tween said pressure-applying locations-and removing the thus displaced plate material from the back of the plate.

5. A process of treating a printing plate comprising preparing a substantially non-resilient t printing plate, building up elevated portions upon a matrix, applying the thus elevated matrix to the printing plate, subjecting the plate and matrix to pressure at a multiplicity of spaced locations to produce depressions upon the printing face of the printing plate, and causing the displaced plate material to enter the spaces between the pressure-applying locations.

6. A process .of treating a printing plate comprising preparing a substantially non-resilient printing plate, building up elevated portions upon a matrix, applying the thus elevated matrix to the printing plate, subjecting the plate and matrix to pressure at a multiplicity of spaced locations to produce depressions upon the printing face of the printing plate, causing the displaced plate I portions to the curved printing plate, and applying pressure to the plate and matrix at a multiplicity of spaced locations with indentations therebetween to simultaneously produce depressions upon the printing face of the printing plate and to force the corresponding protrusions there- 'by produced upon. the back of the plate into the spaces provided by said indentations.

8. A process of treating a curved printing plate comprising applying a matrix having elevated portions of difi'erent heights to the curved printing plate, and applying pressure to the plate and matrix at a multiplicity of spaced locations with indentations therebetween to simultaneously produce depressions of difierent depths upon the printing face of the printing plate and to force the corresponding protrusions thereby produced upon the back of the plate into the spaces provided by said indentations.

9. A process of treating a curved printing plate comprising building up elevated portions upon a matrix, applying the thus elevated matrix to the curved printing plate, and applying pressure-to the plate and matrix at a multiplicity of spaced locations with indentations therebetween to simultaneously produce depressions upon the printing face of the printing plate and to force the corresponding protrusions thereby produced upon the back of the plate into the spaces provided by said indentations.

j 10. A process of treating acurved printing plate comprising applying a matrix having elevated portions to the curved printing plate, subjecting the plate and matrix to pressure at a multiplicity of spaced locations separated by indentatior'is to produce depressions upon the printing face of the printing plate, and causing the displaced plate material to enter the spaces formed by said indentations between said pressure-applying, locations. 11. A process of treating a printing plate consisting of applying a matrix with different elevationsto the printing face of the printing plate,

and subjecting the matrix and printing plate to pressure applied against the back of said plate by a toothed roller adapted to force the correspondingly displaced material at' the back of the the teeth of the pressure roller, and removing 1a thedisplaced portions from the back of the plate.

13. A process of treating a curved printing plate consisting of applying a matrix with difierent elevations to the printing face of the curved printing plate, subjecting the matrix and print- 1:

ing plate to pressure applied against the back of said plate by a toothed rolleryand causing said roller to move in an arcuate path and to force the correspondingly displaced material at the back of the plate into the spaces between the teeth of the pressure roller.

14. A process of treating a curved printing plate consisting of applying a matrix with differl ent elevations to the printing face of the curved printing plate, subjecting the matrix and printing plate to pressure applied against the back of said plate by a toothed roller, causing said roller to move in. an arcuate path and to force the correspondingly displaced material at the back of the plate into the spaces between the teeth of the pressure roller, and removing the displaced portions from the back of the curved printing plate. 15. The process of treating a printing, plate comprising curving the printing plate, thereafter applying a matrix having elevated portions of 5 different heights to the curved printing plate, and subjecting the curved plate and "matrix to pressure to produce depressions of diiferent depths upon the printing. face of the printing plate. r.

'16. The. process of treating a printing plate comprising curving the printing plate, thereafter applying a matrix having elevated portions of diiferent heights to the curved printing plate, and maintaining the curved plate at a substantially constant curvature while subjecting the curved plate and matrix to pressure to produce depressionsof difierent depths upon the printing face of the printing plate.

17. The process of treating a printing plate comprising curving the printing plate to substantially the finally desired curvature, thereafter applying a matrix having elevated portions of different heights to the curved printing plate, and subjecting the curved plate and matrix to pressure to produce depressions of diiferent depths upon the printing face .of the.printing plate while maintaining said curvature substantially un- 

